Service Proxy is created when Drag service to another service in composition.

Until now this service proxy included only the capabilities and requirements of original type, now the requirement is that it will include also all properties, interfaces and Operations of the original service type

Keep service Proxy type as is, just add to it definition the Properties, Attributes and Interface/Operations of original service type - just as we do for capabilities and Requirements

If you look at SDC created CSAR - Service Proxy node type already includes all capabilities and Requirements from original service - so question is how complicated it would be to do the same for Properties/Attributes and for Interface/Operations